Slow disk performance - 1vdev or 3vdevs?

[RichTJ99]

Hi,
I have two Truenas 12 running on two different ESXI servers, similar specs.
Both Truenas VM's have 48 gb of ram , 6 cpu

Tested using:

Code:

dd if=/dev/zero of=/mnt/Pool8/1.iso bs=4M count=10000

Truenas VM 1 has: Sas2308 - 20.00.07 IT - Sas9206-16e
IOM6 Netapp1 disk shelf
two pools, similar performance:
Pool 1 - 6x8tb Z2 - 2963.5 Megabytes @ 13.49 seconds
Pool 2 - 4x10tb Z1 - 2961.36 Megabytes @ 13.51 seconds

Truenas VM 2 has: Sas2308 - 20.00.07 IT - Sas9207-8e
IOM6 Netapp2 - 9x8tb drives
Pool test 1 - 9x8tb - Z3 - 1678.48 Megabytes @ 23.83 seconds
Pool test 2 - 3x8tb Z1 Vdev, 3x8tb Z1 Vdev, 3x8tb Z1 Vdev, - 3 vdevs, all 8tb Z1 - 1790.42 Megabytes 22.34 seconds
Pool test 3 - 2x8tb mirror Vdev (4 mirrored vdevs) - 1801.19 Megabytes 16.29 seconds

Physical Freenas (E3-1231 / 32g)
Pool 6x6 Z2 1Vdev - 4777.79 Megabytes 8.37 seconds

I am OK with the VM's having lower speeds due to multifunction but I am confused on why VM 2 is so much slower? Any ideas what I can look for?

Any other testing suggestions?

Thanks,
Rich